Among compounds having an isoquinoline skeleton, there exist a number of compounds useful as pharmaceuticals. However, a few reports have made mention of compounds having an isoquinoline skeleton substituted at the 6th position by an aminosulfonyl group, which include cannabinoid receptor antagonists disclosed in Patent Document 1, mitochondrial F1F0 ATPase inhibitors disclosed in Patent Document 2, and a method for producing a compound having a phenoxy group disclosed in Non Patent Document 1.